In the textile industry, it has long been the practice to store and transport finite quantities of yarn by winding yarn around a central rigid textile yarn carrier. Frequently, the yarn carrier is a body that is cylindrical, conical, frustroconical, or spool-like in shape, although other forms may sometimes be used. The yarn is wrapped around the body of the carrier by rotating the carrier and feeding the yarn to the carrier from a source, so that the yarn is wrapped circumferentially about the carrier. This practice has been found particularly convenient because a relatively large quantity of yarn may be stored in a compact package that is easy to handle and which readily provides for easy removal of the yarn when it is subsequently needed in a textile operation such as weaving or knitting.
The yarn carrier is often cylindrical or frustroconical in shape so that the yarn stored thereon may be easily removed by drawing the loose end of the yarn over the small end of the carrier. A wound segment of yarn on a carrier is sometimes referred to a partial yarn package.
It has been found desirable to wind the yarn on the textile yarn carrier so that a yarn "tail" extends from the base of the carrier. The yarn tail is provided so that the end of the yarn on a first yarn package may be tied to the leading end of the yarn on a successive yarn package. Then, when all the yarn on the first yarn package has been consumed, the yarn on the second package will be drawn off for use. This arrangement has been found particularly advantageous when the wound yarn packages are used on automatic textile machinery, such as looms, circular knitting machines or the like, since the knitting or other textile machine may be operated continuously even though the first yarn package may have been exhausted.
The yarn tail is generally formed prior to winding the yarn on the carrier. A yarn segment is first extended linearly across the base of the carrier transverse to the longitudinal axis of the carrier. When winding is accomplished on an automatic yarn winding machine, the carrier is then urged by mechanical means into engagement with a rotatable end holder cap, which may also be called a base plate or chuck, having a suitable size for mating with the open bottom end of the yarn carrier. The relatively smaller upper end of the yarn carrier is engaged by a nose cap or nose holder, which is also rotatable. Some other suitable holder or support for the nose of the yarn carrier may also be used. The end holder cap and nose cap are arranged to grip the carrier so that it can be driven in rotary fashion by associated winding apparatus.
Generally, the yarn tail is trapped between the end holder cap and textile yarn carrier by the engagement thereof. Rotation of the yarn carrier and end holder cap pulls the yarn towards the carrier from a yarn source, thus causing the yarn to be wrapped circumferentially about the outer face of the carrier. The position of the yarn along the length of the carrier is moved over the length of the carrier to distribute the yarn evenly over the carrier. After numerous rotations, a sufficient amount of yarn may be wound about the outer face of the carrier.
In the past, the industry has encountered problems with abrasion or severance of the yarn tail during the winding process due primarily to engagement of the yarn tail between the textile yarn carrier and the end holder cap. For example, the yarn tail may be severed when the yarn carrier is urged into position against the end holder cap. Frequently, the yarn may be broken by a pinching action generated between the end holder cap, base plate or chuck and the yarn carrier while the carrier and end cap are in rotation. Alternatively, the yarn may be severed due to relative, sliding motion between the yarn tail and the yarn carrier as the yarn carrier is rotated. Severance of the yarn tail is sometimes caused by burrs or other irregularities on the inner or bottom faces of the textile yarn carrier.
Yarn tail breakage and abrasion problems are generally exacerbated when the yarn carrier is made of a relatively hard material such as plastic or the like. For example, the bottom edge and inner face of a hard, plastic yarn carrier may not be sufficiently resilient for the face of the yarn carrier to "give" or form an indentation for receiving the yarn tail when the carrier is positioned on an end holder cap or chuck. Thus, the presence of the yarn interferes with the loading of the carrier onto the end holder cap. As a result, the force that is used to urge the carrier onto the cap is localized, at least in part, on the portions of the yarn tail that extends between the base of the carrier and the end holder cap. In contrast, if the carrier were made of a softer, more resilient material such as paper or cardboard, the interference between the yarn and the carrier could be alleviated by localized indentation of the fibers comprising the body of the carrier.
In recognition of these problems, one prior attempt to minimize yarn severance has focused on polishing, or beveling, the corner between the bottom annular face and inner face of the textile yarn carrier, as shown in U.S. Pat. No. 5,014,928 to Gandy, et al. The Gandy '928 approach, however, has been found useful primarily for textile yarn carriers made of paper having fibers that are relatively soft, which provide a cushion for the yarn tail when trapped between the carrier and the end holder cap.
Another prior attempt to minimize yarn tail breakage is seen in U.S. Pat. Nos. 4,700,834 and 4,700,904 to Martinez. The Martinez '834 and '904 patents describe a plurality of short, relatively narrow, spirally extending grooves formed in the inner face of the textile yarn carrier for gripping the yarn to prevent breakage of the yarn by relative movement between the yarn carrier and the end holder cap. However, this approach is not believed to have sufficiently alleviated the problem of yarn tail breakage.